Semiconductor devices typically comprise multiple layers of conductive, insulative, and semiconductive layers. Crystalline materials, such as silicon, are often employed to serve various functions, especially in the semiconductor and insulator materials. Various properties of such layers tend to improve with the crystallinity of the layer. For example, electron charge displacement and electron energy recoverability of an insulative layer improve as the crystallinity of the layer increases. The amount of charge that can be stored is a function of the dielectric constant of the insulative layer. Further, improved insulative properties tend to reduce the power consumption and size of various components, such as capacitors.
For example, a capacitor generally comprises two conductive elements separated by a dielectric layer. Single-crystal materials exhibit excellent insulative properties, but efforts to construct capacitors with single-crystal dielectric layers have not been particularly successful. These attempts have generally been unsuccessful, at least in part, because lattice mismatches between the host crystal and the grown crystal cause the resulting layer to be of low crystalline quality. Such efforts commonly result in polycrystalline dielectric materials, and the insulating properties of such materials are compromised by defects and grain boundaries. Defects and grain boundaries tend to allow greater leakage current through the dielectric layer, degrading the effectiveness of the insulator. Consequently, conventional devices typically include additional protection layers to prevent the inclusion of foreign materials, defects, and grain boundaries.
To reduce the leakage current, many capacitors include additional dielectric layers, typically formed from amorphous materials, such as amorphous zirconium titanate. Adding layers, however, requires additional processing steps and materials. Further, the properties of such layers are more difficult to control than crystalline materials.